DESCRIPTION: (Taken from the applicant's abstract) The long term objective of this project is to further examine these specific changes to identify basic mechanisms responsible for the plasticity observed in the dorsal horn after regeneration of severed nerves. Combined electrophysiological and anatomical methodology coupled with single fiber recording and stimulation techniques will be used to determine: 1) if the population of sprouting fibers make aberrant connections with dorsal horn cells and/or if any properties unique to them can be identified; 2) what specific spinal mechanisms are involved in reconstruction of concise dorsal horn cell receptive fields; 3) if formation of new functional connections aid in the consolidation of dorsal horn cell receptive fields; 4) if more detailed analysis of the integration of somatosensory inputs in intact preparations can enhance our knowledge of these plastic events. The information obtained should enable the identification of specific mechanisms involved in the observed plasticity. Once identified these mechanisms can then be studied further to determine if certain manipulations could perhaps reduce the inappropriate collateral sprouting or enhance the ability of dorsal horn cells to construct concise receptive fields.